Mold, method and installation for blow-molding thermoplastic containers provided with an integral handle, and container thus produced
AssigneeSidel Participations
InventorsOlivier Jacson, Marc Michelet
Life of this patent
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Abstract
The invention relates to a mold for the production by means of blowing or blow-drawing of thermoplastic containers which are equipped with an integral handle. According to the invention, two mold halves are provided with two respective inserts which can move transversely to the contact faces. Each of the aforementioned inserts comprises two telescopic pistons, namely: a main piston having a front thrust face, and a secondary piston which is housed in the main piston and which has a curvilinear front weld face. The secondary pistons are moved after the main pistons have applied two wall zones of the container body against one another.
Claims14
A mold for manufacturing, by blow molding or stretch-blow molding of a heated preform, a container made of thermoplastic material, in particular a polyolefin such as polypropylene, provided with an integral handle, said mold comprising at least two mold halves which
- are movable relative to one another,
- have respective mutual contact faces defining, in a closed position, a junction plane,
- have respectively two imprints which, joined together, define a molding cavity of the body and the shoulder of the final container, and
- comprise respectively two recesses which are substantially perpendicular to said respective contact faces and substantially mutually aligned in the closed position of the mold and which enclose two respective inserts forming pistons which can be moved pneumatically between
- a retracted position in which the two inserts are returned, at least for the most part, into their respective recesses and
- an extended position in which the two inserts are pushed together by pinching two given wall zones of the body of the container until said two wall zones of the body, which are then heat-welded together, are brought into mutual contact,
- wherein each insert comprises two pistons telescoped one within the other, namely a main piston or thrust piston having a centrally located front thrust face and, accommodated in said main piston, a coaxially arranged secondary piston or welding piston having a front face surrounding said front face of the main piston along a closed contour coinciding with the periphery of said wall zone of the body of the container, heating means being provided for keeping at least said front face of the secondary piston at the softening temperature of the thermoplastic material, the two pistons, the main piston and the secondary piston, being arranged in such a way that
- in a first operating phase, the main piston is moved from its retracted position to its protruding position, whereas the secondary piston remains retracted in said main piston, the front face of said main piston pushing said given zone of the wall of the body of the container, and
- in a second operating phase, the secondary piston is moved relative to the main piston from its retracted position to its protruding position in such a way that its hot front face rests against the periphery of said wall zone of the body of the container in order to soften the material thereof, to weld it peripherally with the wall portion pushed by the opposing piston, and at least to premark the perimeter of this wall zone.
A method for manufacturing, by blow molding or stretch-blow molding of a heated preform, a container made of thermoplastic material, in particular a polyolefin such as polypropylene, provided with an integral handle by use of a mold comprising at least two mold halves which
- are movable relative to one another,
- have respective mutual contact faces defining, in a closed position, a junction plane,
- have respectively two imprints which, joined together, define a molding cavity of the body and the shoulder of the final container, and
- comprise respectively two recesses which are substantially perpendicular to said respective contact faces and substantially mutually aligned in the closed position of the mold and which enclose two respective inserts forming pistons which can be moved pneumatically between
- a retracted position in which the two inserts are returned, at least for the most part, into their respective recesses and
- an extended position in which the two inserts are pushed together by pinching two given wall zones of the body of the container until said two wall zones of the body, which are then heat welded together, are brought into mutual contact,
- wherein
- each insert is formed with two pistons telescoped one within the other, namely a main piston or thrust piston having a centrally located front thrust face and, accommodated in said main piston,
- a coaxially arranged secondary piston or welding piston having a front face surrounding said front face of the main piston along a closed contour coinciding with the periphery of said wall zone of the body of the container,
- heating means are provided for keeping at least said front face of the secondary piston at the softening temperature of the thermoplastic material,
- and the two pistons, the main piston and the secondary piston, are configured in such a way that
- in a first operating phase, the main piston is moved from its retracted position to its protruding position, whereas the secondary piston is kept retracted in said main piston, the front face of said main piston pushing said given zone of the wall of the body of the container, and
- in a second operating phase, the secondary piston is moved relative to the main piston from its retracted position to its protruding position in such a way that its hot front face rests against the periphery of said wall zone of the body of the container in order to soften the material thereof, to weld it peripherally with the wall portion pushed by the opposing piston, and at least to premark the perimeter of this wall zone.
Dependencies are inferred from the claim text.